The invention relates generally to a testing apparatus and, more particularly, to a tool and method for measuring the flow characteristics of molding compounds.
Among the devices available for testing plasticity and flow characteristics of materials is a plastometer which is disclosed in U.S. Pat. No. 3,033,021. That device includes a mold element having a pair of cavities. A passage leads between the cavities and a plurality of troughs extend radially outwardly from one of the cavities. The troughs are provided for forcing material received within the other one of the cavities through the passage and into the one cavity and the associated troughs. The flow characteristics of the material are measured by the distance of flow of the material in the troughs.
Another prior art device includes a transfer press with an Archimedean spiral mold cut into the fixed platen. However, the mold has a relatively small cross-sectional area. In order to test sheet molding compound with one inch or more glass fiber reinforcing material lengths, the sheet must be cut into smaller pieces which tends to produce inaccurate test results.